1. Field of the Invention
This invention relates to evaporative cooler pumps and, more particularly, to a single suction inlet evaporative cooler pump having a bearing seal and seal elements for the impeller housing of the evaporative cooler pump where the motor shaft extends into the impeller housing.
2. Description of the Prior Art
Evaporative cooler pumps have an impeller housing at the bottom of the pump and a motor at the top of the pump. Extending between the motor and an impeller in the impeller housing is a relatively long motor shaft. The shaft extends into the impeller housing through a relatively large diameter hole or aperture in the top of the housing. The primary reason that the hole or aperture in the top of the housing is relatively large is for convenience in the assembly of the motor to the pump housing. That is, the location of the motor or impeller shaft with respect to the hole or aperture may vary, depending on the type of motor used, the manner in which the motor is secured to the housing, and other variables. Thence the need for a hole that is substantially larger than the shaft diameter.
A secondary reason for a relatively large hole is that an eccentric motion of the shaft is not uncommon. Accordingly, a relatively large diameter hole or aperture is generally required. This relatively large diameter hole is an integral element in each evaporative cooler pump.
One of the inherent limitations of evaporative cooler pumps due to the hole in the top of the impeller housing is the necessity of a relatively high water level in the pan of the evaporative cooler. If the water level drops too close to the top of the impeller housing, the presence of the hole through the top of the impeller housing causes air to be sucked into the impeller housing, and there is a corresponding loss of efficiency of the pump itself.
Another inherent limitation of evaporative cooler pumps, or an inherent problem with them, due to the relatively large hole, is the upward slinging or rise of water or water particles along the shaft and to the pump motor. This results in rust and corrosion problems and in the eventual premature failure of the motor.
If the impeller shaft were sealed at the housing, the water level could be lowered by a substantial amount, like about an inch or so, without having any effect on the efficiency of the pump itself. The water level could then be almost as low as the water inlet at the bottom of the pump housing, that is, below the top of the impeller housing. Moreover, the upward movement of water particles along the shaft to the motor is substantially prevented.
While there has thus been a need to provide a seal for the shaft at the impeller housing, no such element has been successfully developed in the prior art. Any such seal would have to provide a dual function, a seal would have to be provided and a bearing seal for the shaft would have to be provided. In addition, the seal would have to be sufficiently flexible to compensate for eccentric shaft movements, and the like.
The apparatus of the present invention overcomes the deficiencies of the prior art and provides a seal for the impeller housing and a bearing seal for the impeller shaft.